But when i want watch 3D video, need get real resolution 1280x800 (120 Hz) to synchronize with active 3d glasses. This mode supported by projector (tested by Nvidia's videocard) and avaliable in Intel HD driver on HDMI output, but when i select and apply it, projector says "Unsupported mode".

I think, this is happens because Intel HD driver simply scales resolution and doesn't change real resolution from 1920x1080 to 1280x800. In this case Intel HD driver tries send signal with 1920x1080 @ 120 Hz and this is reason of projector's error.

And the most important thing, that all working fine when i connect projector to VGA output: for example, i can set 1024x768 @ 120 Hz, and Intel HD driver sends real signal with 1024x768 @ 120 Hz ! (projector reports real resolution), so i can properly synchronize my 3d glasses. But i don't want to use VGA output, because image is worse than via HDMI.